This SD card module, or Secure Digital card, is a non-volatile solid-state flash memory. Meaning if we disconnect power, it will retain its data.With an SD card we can expand Arduino's permanent storage by gigabytes.

1) You just need to connect to Arduino interrupt pin 2, and can measure the number of PWM pulse/interrupt per unit of time. The water flow would be directly proportional to the number of measured pulses. 2)Water flow sensor can be used to measure the flow of liquids, i.e. the consumption of liquids in industrial or domestic usage.

Can detect the flame or wavelength at 760 nm to 760 nm range of light sources. Detection point of about 60 degrees, particularly sensitive to the flame spectrum. Sensitivity is adjustable, stable performance. Working voltage 5V, digital analog output. Fire fighting robot necessary parts. The main selling point is flame sensor. Main use: flame detection.